The use of packet-based networking has been growing over time and the growth in traffic demands is increasingly being met by introducing ever larger monolithic routers. However, this model is approaching its technologic and economic limits. It is more and more difficult to fulfill the increasing demand for bandwidth with traditional router designs, and with the emergence of low cost Commercial Off-The-Shelf hardware, router vendors also have difficulty justifying higher costs for the same performance. At the same time, the demands on the routing and switching control plane in the access and aggregation networks are becoming more complex. Operators want the ability to customize packet delivery to handle specific kinds of traffic flows without the detailed low-level configuration typical of today's networks.
These trends suggest a different approach to the network architecture, in which the control plane logic is handled by a centralized server and the forwarding plane consists of simplified switching elements “programmed” by the centralized controller. Software Defined Networking (SDN) is a new network architecture that introduces programmability, centralized intelligence and abstractions from the underlying network infrastructure.
Along with the spread of Cloud Computing, network virtualization is highly used in Data Center networks. The popularity of virtualization results from flexible and efficient management, it makes the infrastructure provider networks more profitable, allows new features and dynamic usage model and helps data center tenants to decrease their capital expenses. In data center networks, virtual network resources such as virtual switches and routers are shared among multiple tenants to reduce physical resources and power costs. Thus, a challenge is to isolate virtual data center networks (vDCNs) of a large number of tenants. In addition to adopting Network Virtualization, as applications get virtualized in virtual machines (VMs), it challenges many aspects of traditional networking Network architectures limitations are realized, especially for big-data workload setting, traffic changing and resources sharing between tenant's vDCNs. In both centralized and distributed architecture, one may have all the privileges to configure each network bandwidth, security-policies (e.g. firewalls), subnets, virtual local area networks (vLANs) and quality of service (QoS). These configuration steps evolve with the complexity of today's networks and make it difficult to apply a consistent set of access controls and implement a network-wide isolation.
Typically, tenants are not given full access control over virtual routers or switches which are operated by the service provider/data center operator in their multi-tenant vDCNs. Providing transparency and self-management for multi-tenant vDCNs represents a need which must be preceded by performance isolation to be realizable. It is widely accepted that the network of the future will require a greater degree of service awareness and optimal use of network resources. It is becoming primordial that future networks should be both self-controlled and management-aware, which includes the scale in/out of network domains.
Creating “virtual slices” is an issue that has not been completely resolved prior to the introduction of SDN mechanisms such as OpenFlow. OpenFlow is a standard protocol between the control and forwarding planes used in SDN applications. OpenFlow was initially designed for Ethernet-based forwarding engines, with internal flow tables and a standardized interface to add and/or remove flow entries. The flow tables specify how the switch should process packets, with an entry of actions associated with each flow. The OpenFlow protocol provides an open and standard method for an OpenFlow switch to communicate with an SDN controller.
SDN concepts have gained attention due to their flexibility for creating separate and independent virtual networks on top of physical network infrastructures. SDN mechanisms enable the dynamic configuration of an entire network using a control brain in an open approach, and this flexibility by decoupling the control and data planes is beneficial for cloud data center networks consisting of many virtual switches/routers, computing nodes, and users' virtual machines. OpenFlow enhances network flow control by allowing a fine manipulation of each incoming packet to determine the forwarding port on-the-fly based on dynamically set flow rules and altering destination address or path.
SDN implementations to date have made use of a single centralized or distributed controller to achieve architecture isolation between different customers, but without solving networks scalability bottlenecks and arriving at a consistent solution to solve vDCN isolation and highly flexible scaling collaboration. A tenant's vDCNs needs to be scalable, on-demand and orchestrated.
Therefore, it would be desirable to provide a system and method that obviate or mitigate the above described problems.